From: beckwb@ois.com (R. William Beckwith)
Subject: Re: Ada95 and Dynamic Type Identification
Date: 18 Jan 1995 14:12:17 -0500
Date: 1995-01-18T14:12:17-05:00 [thread overview]
Message-ID: <3fjp6h$9ad@gamma.ois.com> (raw)
In-Reply-To: milodD2Ko8z.98w@netcom.com
John DiCamillo (milod@netcom.com) wrote:
: Does Ada95 have some sort of dynamic type identification
: equivalent to C++ RTTI or Eiffel's assignment-attempt?
: That is, given a procedure
: procedure Process_Alerts(A: Alert'Class) ...
: Is there any way to find out precisely what type of
: object A is? Or are we limited to dynamic dispatch?
: e.g.:
: foo: FooAlert; -- special alert
: begin
: foo ?= A; -- is A a FooAlert?
: if (foo'Valid) then -- A IS a FooAlert!
: FooHandler( foo ); -- do something that only
: -- applies to FooAlerts
4.5.2 Relational Operators and Membership Tests
if A in FooAlert'CLASS then -- is A a FooAlert?
FooHandler(FooAlert'CLASS(A)); -- do something that only
end if; -- applies to FooAlerts
The FooAlert'CLASS(A) type conversion is thus guaranteed
to work.
: Anyway, if dynamic typing was left out of Ada95, would
: that be considered a mistake. Every other statically
: typed OOPL I know of has eventually provided some form
: of dynamic typing. Why not Ada? Is there some subtlety
: about Ada's type system that makes dynamic typing un-
: necessary or irrelevant?
Yes, leaving dynamic typing would have been a mistake.
I'm sure glad Ada95 has such a nice dynamic typing system.
... Bill
prev parent reply other threads:[~1995-01-18 19:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <milodD2Ko8z.98w@netcom.com>
1995-01-18 8:48 ` Ada95 and Dynamic Type Identification Stephane Barbey
1995-01-18 12:39 ` Robert A Duff
1995-01-18 17:33 ` David Moore
1995-01-18 19:12 ` R. William Beckwith [this message]
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